Nicol and Moore were found guilty of murdering Mr Blackwood in Saltcoats, North Aryshire, on 3 July or 4 July last year.

They were both sentenced to life imprisonment and ordered to serve at least 20 years each before being eligible for parole.

Smith was convicted of the lesser charge of killing Mr Blackwood following a five-week trial at the High Court in Glasgow. She will be sentenced next month.

Judge Lord McEwan said: “This was a scandalous, disgraceful and horrific attack on a young man including what amounted to torture.”

A pathologist later said the head injuries found on the victim were usually encountered in a car crash victims or people who had fallen from a great height.

Mr Blackwood, described by prosecutors as vulnerable, was relentlessly bullied by the gang before he was set upon last July. He had known his attackers for some time.

During the trial, the court heard that Smith claimed the fatal attack itself was sparked by the belief that Mr Blackwood was seeing Moore’s girlfriend Laura Johnstone behind his back – which the court later heard was false.

Witness Sean Sinclair, 21, told how he went to Nicol’s home on the night of his murder and discovered an already badly beaten Mr Blackwood.

He said Moore stood over the victim armed with a metal pole covered in blood.

In a police interview, witness Sinclair, 21, said: “Tommy hit Scott with the barbell. Alan started laying into Scott on the side of the legs.